package com.lc.hot100.lc70;

public class Main {
	public static void main(String[] args) {
		
	}
}

class Solution {
    public int climbStairs(int n) {
    	int p = 0, q = 0, r = 1;
    	for (int i = 1; i <= n; i ++) {
    		p = q;
    		q = r;
    		r = p + q;
    	}
    	return r;
    }
}
